The present invention relates in general to improvements in grating structures of a type in which a grating panel or pair of panels formed as a generally rectangular reticulated grating structure provides a cover at road surface level for storm drain inlets and similar type road surface openings to form a uniform traffic-bearing grating surface over which motor vehicles, bicycles and the like are adapted to travel, and more particularly to grating structures of such type having manually manipulatable adjustment and locking structure for adjustably positioning the grating transversely in the stationary supporting frame structure for the grating and including locking mechanism to be interlocked with the supporting frame for preventing and discouraging the removal of the grating structure from the drain inlet.
Replaceable grating devices in the form of rigid grating panels have been customarily employed as the roadway surface level cover for storm drain inlets spaced at intermittent locations along the curb region of highways and city streets. The road drain inlet gratings for such highway storm drain inlets and the like designed to withstand the load of automobile and bicycle traffic, have frequently been formed of cast iron grating panels adapted to be supported in the customary stationary frame at the upper inlet opening of the standard concrete storm drain inlet box, frequently having transversely spaced elongated longitudinal slot-like openings separated by rigid cast bar formations longitudinally spanning the length of the grating panel to provide a large total opening area for passage of water into the storm drain inlet box. These customary highway storm drain inlet gratings are produced with various opening patterns, but most frequently have the transversely spaced, elongated slots longitudinally spanning the grating panel with the slots either extending uninterruptedly over most of the length of the grating panel or being interrupted by a few transverse webs.
More recently, as a result of a number of bicycle accidents caused by penetration of the narrower style bicycle tires in current vogue into the slots or passages in the cast highway inlet gratings of the elongated slotted design, replacement of the slotted design gratings with reticular gratings having smaller nonelongated openings which would provide greater bicycle safety has been undertaken in many areas. Similar reticular gratings, formed of parallel longitudinal bearing bars and intermediate crimped strips, have been used as decking for traffic-bearing surfaces such as bridges, elevated highways, sidewalk covers for below ground ventilating inlets and freight access tunnels, or reticulated flooring sections in industrial plants. The need to remove large numbers of the road drain inlet gratings from their supporting frames and replace them with grating structures of other designs has increased awareness of the need for improvement in the means for anchoring or fastening such grating structures in place to prevent or discourage the removal of the grating by unauthorized personnel. Typically, it has been recommended for positive fastening and easy, rapid installation of conventional reticulated gratings that the bearing bars be spot welded at various locations to the supporting angle iron structure or other supporting frame. Of course such spot welded fastening techniques for gratings make it a difficult, time-consuming and expensive procedure to remove the grating when its removal and replacement is called for. Where it is recognized that periodic removal of the grating may be required, some have proposed various types of locking devices such as shouldered slotted slide plates secured by bolt and nut fasteners to the grating, or clip type or bendable fastening devices secured by screws or bolts to the grating to interfit with or against various surface formations of the associated supporting frame and fasten the grating against removal. Frequently, these anchoring devices include portions which protrude upwardly above the upper traffic-bearing surface formed by the grating structure, thus providing undesirable characteristics.
Also, some specifications for grating panel structures for highway storm drain inlets require that the grating panel structure include some kind of adjustment device which may be adjustably positioned laterally outwardly from the curb side outermost longitudinal bearing bar or straight side member of the grating panel to bear against the confronting member of the stationary supporting frame surrounding the inlet opening of the storm drain inlet to enable the grating panel to be inserted in the frame and adjustably positioned laterally to the desired position in the frame. This adjusting device sometimes is a required feature of grating panels for storm drain inlets to facilitate the installation and removal of the grating panels.
An object of the present invention is the provision of a novel grating panel structure for the framed inlet opening of conventional highway storm drain inlets and the like, wherein the grating structure includes a stationary outwardly projecting anchoring leg at the road side of the grating panel to project under the associated stationary grate supporting frame of the storm drain inlet and includes an adjustable locking device at the curb side of the grating panel having a modified angle formation adjustably supported by the adjacent side member of the grating for movement outwardly toward and away from the grating side member providing a bearing face to abut the inside vertical face of the associated stationary frame and providing another leg to project under the adjacent stationary frame portion to anchor the grating in position against unauthorized or accidental removal.
Another object of the present invention is the provision of a novel grating panel structure as described in the immediately preceding paragraph, wherein the adjustable locking structure includes a threaded stud extending through a side bearing bar member of the grating panel having an angle iron foot member on the end thereof to bear against the confronting inside vertical face of the associated stationary frame and under the adjacent portions of the stationary frame and having adjusting nut members on the threaded stud for determining the adjusted positions of the angle foot member.
Other objects, advantages and capabilities of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings illustrating a preferred embodiment of the invention.